U.S. patent number 4,685,801 [Application Number 06/814,169] was granted by the patent office on 1987-08-11 for apparatus for absorptiometric analysis.
This patent grant is currently assigned to Tokyo Shibaura Denki Kabushiki Kaisha. Invention is credited to Tomiharu Minekane.
United States Patent |
4,685,801 |
Minekane |
August 11, 1987 |
Apparatus for absorptiometric analysis
Abstract
The beam from a xenon flashed lamp driven by a pulse drive
system is guided through 12 illumination beam guiding optical
fibers, to illuminate a reaction liquid contained in 12 reaction
cuvettes (with every 4 reaction cuvettes being located at each of 3
different measuring stations). The beam transmitted through the
reaction liquid is so led as to be incident on 12 transmitted beam
guiding optical fibers. The beam emission ends of the transmitted
beam guiding optical fibers are inserted into a support member at
positions thereof which fall on a circle. The rotor is rotated in
conjunction with a shaft. A pair of reflecting mirrors are secured
to the rotor and shaft, respectively. The beams emitted from the
transmitted beam guiding optical fibers are independently and
consecutively led along the same optical path, to a pair of slit
members disposed on the side of the rotor opposite the support
member, while the rotor completes one rotation. The beam passed
through the slit members is diffracted by a diffraction grating,
and diffracted beams are detected by a photodetector array.
Inventors: |
Minekane; Tomiharu (Ootawara,
JP) |
Assignee: |
Tokyo Shibaura Denki Kabushiki
Kaisha (Kawasaki, JP)
|
Family
ID: |
16071271 |
Appl.
No.: |
06/814,169 |
Filed: |
December 23, 1985 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
541658 |
Oct 13, 1983 |
|
|
|
|
Foreign Application Priority Data
|
|
|
|
|
Oct 15, 1982 [JP] |
|
|
57-179753 |
|
Current U.S.
Class: |
356/328; 422/63;
422/82.09; 436/47 |
Current CPC
Class: |
G01N
21/253 (20130101); G01J 3/2803 (20130101); Y10T
436/113332 (20150115); G01N 2201/08 (20130101) |
Current International
Class: |
G01N
21/25 (20060101); G01J 3/28 (20060101); G01J
003/08 (); G01J 003/42 () |
Field of
Search: |
;356/326,328,319,409-411,432,433,436,440 ;436/34,43,47
;422/63-65,68 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2451769 |
|
May 1975 |
|
DE |
|
2408543 |
|
Aug 1975 |
|
DE |
|
2469713 |
|
May 1981 |
|
FR |
|
151084 |
|
Nov 1979 |
|
JP |
|
72108 |
|
Apr 1983 |
|
JP |
|
Primary Examiner: Evans; F. L.
Attorney, Agent or Firm: Cushman, Darby & Cushman
Parent Case Text
This is a continuation of application Ser. No. 541,658, filed Oct.
13, 1983, which was abandoned upon the filing hereof.
Claims
What is claimed is:
1. An apparatus for measuring absorbances of samples contained in
reaction vessels, comprising:
illuminating means for emitting light beams;
measuring means for measuring the intensity of the light beams
transmitted through the samples contained in the vessels;
transfer means for transferring reaction vessels successively
forwarded to predetermined measuring points on a reaction line;
guiding means having stationary optical fibers, each with a
beam-receiving end and a beam-emitting end, for guiding through a
first portion of said stationary fibers light beams emitted from
the illuminating means to the samples contained in the respective
vessels staying at the measuring points, and for guiding through a
second portion of said stationary fibers the light beams
transmitted from the respective samples to the measuring means;
switching means for selecting one transmitted light beam through
the reaction vessel staying at one measuring point, and directing
the selected beam to the measuring means, said switching means
including;
(a) a holder for holding the optical fibers, the beam-emitting ends
of which are arranged so that the light beams passing through the
optical fibers are emitted substantially simultaneously from the
respective beam-emitting ends of the optical fibers;
(b) a first mirror for reflecting one light beam transmitted from
the corresponding fiber;
(c) a rotating member for rotating the first mirror to align the
same with the beam-emitting ends of said optical fibers one after
another, so that said first mirror reflects the light beams from
the corresponding fibers, the first reflecting mirror scanning the
beam-emitting ends of all optical fibers held by the holder, every
time the first mirror rotates when the vessels stay at the
measuring points; and
(d) a second mirror for reflecting said light beam reflected from
said first mirror and passing it through a common light path to
said measuring means, regardless of the position of the optical
fiber aligned with the first mirror;
a plurality of slit members disposed along the common light path;
and
a diffraction grating, disposed along the common light path
downstream of said slit members, for diffracting the beam that has
passed through said slit members.
2. The apparatus according to claim 1, wherein the illuminating
means includes a light source, which is driven by a pulse drive
system to emit said light beams, such as any one of a xenon flashed
lamp, a mercury flashed lamp and a pulse laser.
3. The apparatus according to claim 2, wherein said guiding means
further includes beam path defining members, each of which is used
for directing the beam emitted from each of the illumination beam
guiding optical fibers to the samples in each of the reaction
vessels; and condenser lenses, each of which is interposed between
each of the beam path defining members and the beam emission end of
each of the illumination beam guiding optical fibers.
4. The apparatus according to claim 3, wherein said guiding means
further includes transmitted beam path defining members, each of
which is used for directing the beam transmitted through the
samples in each of the reaction vessels to the beam receiving end
of each of the transmitted beam guiding optical fibers; and
condenser lenses, each of which is interposed between each of the
transmitted beam path defining members and the beam receiving end
of each of the transmitted beam guiding optical fibers.
5. The apparatus according to claim 2, wherein the switching means
further includes a shaft having an axis coaxial with the center of
the circle of the holder and extending parallel to the beams
emitted from the transmitted beam guiding optical fibers, the shaft
being rotatably supported in the holder, and a rotor being secured
to the shaft; and, wherein, the following conditions apply; the
first reflecting mirror is secured to the rotor; the second
reflecting mirror is secured to the shaft; the rotor has a
see-through hole, through which the path of the beam reflected by
the second reflecting mirror extends; and the transmitted beam
emitted from each of the transmitted beam guiding optical fibers is
reflected by the first and second reflecting mirrors and proceeds
along a substantially constant beam path, through the see-through
hole, while the rotor completes one rotation.
6. The apparatus according to claim 5, wherein the beam emission
end of each of the transmitted beam guiding optical fibers has an
elongate sectional shape, and the elongate beam emission ends of
all of the transmitted beam guiding optical fibers extend in the
same direction.
7. The apparatus according to claim 6, wherein said slit members
are disposed between the rotor and diffraction grating, a condenser
lens being interposed between individual ones of said slit members.
Description
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for absorptiometric analysis
in the field of automatic chemical analysis apparatus and, more
particularly, to an absorbance measuring apparatus which can
quickly effect absorbance measurement processes on a number of
samples for a plurality of measurement items.
FIG. 1 shows a conventional absorbance measuring apparatus. A beam
emitted from a light source 10 is incident on a bundle of optical
fibers 12 and is led through these optical fibers 12 to reaction
tubes 20 for a plurality of channels located in, for instance,
three measuring stations, i.e., first to third measuring stations
14, 16 and 18. In the illustrated example, each measuring station
has four channels, though a reaction tube for only one of these
channels is shown for each measuring station. Reflecting mirrors 22
are each disposed on the side of each reaction tube 20 opposite the
beam emission end of the corresponding optical fiber. The beam
emitted from each optical fiber 12 is transmitted through a
reaction liquid contained in each reaction cuvette 20 and is then
reflected by each reflecting mirror 22. Beams reflected from the
individual reflecting mirrors 22 are incident on two-wavelength
spectrometers 24, 26 and 28, respectively. Each of the
two-wavelength spectrometers includes a beam splitter 30 and
spectrometers 32 and 34. The beam splitter 30 splits the incident
beam into two light beams which are led to the pair of
spectrometers 32, 34. The spectrometers 32, 34 each include a
filter and a photo-detector, and can measure the intensity of
transmitted light of particular wavelengths.
A sample serum, for example, is distributed to the reaction tubes
20 for four channels, and different reagents for the respective
channels are poured into the sample serum in the individual
reaction tubes 20. The reaction tubes 20, each of which contains
the reaction liquid, i.e., the mixture of sample serum and reagent,
are brought to the successive first to third measuring stations 14,
16 and 18, and the intensity of the transmitted beam is measured
for two different wavelengths at each of the measuring stations.
Changes in the absorbance (i.e., the reaction degree) of the
reaction liquid, over time, can thus be measured, whereby an
examination can be conducted for four different channels of items
(such as GOT and GPT) in the respective samples.
In this absorbance measuring apparatus, two-wavelength
spectrometers 24, 26, 28 must be provided for the individual
channels at the respective measuring stations. Therefore, the cost
and size of the apparatus are increased to that extent. Further,
since changes in the absorbance of each reaction liquid, over time,
are measured by different two-wavelength spectrometers 24, 26, 28,
the results of examination are subject to error, due to variations
in the light-electricity conversion characteristics among the
individual two-wavelength spectrometers 24, 26, 28. This is a
serious drawback; and, where examination is done by measuring the
enzyme activities of GOT or GPT, which can undergo fewer absorbance
changes, the drawback is so serious that the examination becomes
impossible. Moreover, the optical fibers 12 have a low filling
factor, so that a high output halogen lamp which continuously emits
light is used as the light source 10. A beam of such a high energy
level, however, would cause decomposition of a reaction liquid
obtained from, for instance, the serum of a jaundice patient, thus
disabling accurate examination.
FIG. 2 shows a different conventional absorbance measuring
apparatus. In this case, a plurality of reaction cuvettes 46 are
disposed along a circle for each of the different channels 36, 38,
. . . . The reaction cuvettes 46 for each channel are moved about
the center of the circle. When each reaction cuvette 46 is at an
absorbance measuring position, a beam emitted from a light source
48 is converged by a condenser lens 50 and transmitted through the
reaction liquid in the reaction cuvette 46. The transmitted beam is
passed through a slit 52 to be incident on a diffracting grating
54. Diffracted monochromatic light beams from the diffracting
grating 54 are detected in a photodiode array 56. In each of the
channels 36, 38, . . . a particular item of examination is done,
that is, the same reagent is poured into the reaction cuvettes 46
in the same channel. A sample, e.g., a serum, is distributed
through a tube 42 and pipette 44 into the reaction cuvettes 46 in
the same channels 36, 38, . . . . In each tube, it is mixed with a
reagent so that a reaction liquid is produced. Changes in the
absorbance of the reaction liquid with time are measured by each
diffracting grating 54 and photodiode array 56.
In this apparatus, the absorbance is measured by the same
spectrometer (i.e., by diffracting grating 54 and photodiode array
56) for each particular item, and the measurement is thus free from
errors due to fluctuations of the spectrometer's detection
characteristics. However, the light source 48 must be provided for
each channel. Therefore, the operation and service are rather
cumbersome. In addition, high power must be consumed for driving
the light sources. Further, the size of the apparatus is inevitably
large.
According to the invention disclosed in U.S. Pat. No. 3,697,185,
while a sample such as a serum flows through a tube, a reagent is
added to the sample, and the absorbance of the resultant reaction
liquid is measured under temperature-controlled conditions. The
measurement of absorbance is done by causing filtered beams of
particular wavelengths to be incident on the reaction liquid at
successively provided measuring stations.
In this apparatus, measuring stations are provided for the
respective wavelengths of the absorbance measurement, so that an
enlarged apparatus is again inevitable. In addition, it is probable
that stray light which is incident on the detector will cause an
error in the detection. Further, the precision of detection is
influenced by the balance of the filter.
SUMMARY OF THE INVENTION
One object of the present invention is to provide an apparatus for
absorptiometric analysis, with which the measurement of absorbance
for a plurality of channels can be done by a single
spectro-photometric means, so that it is possible to obtain high
precision of absorbance measurement and highly reliable examination
results.
Another object of the present invention is to provide an apparatus
for absorptiometric analysis, which can use a single and common
light source in the absorbance measurement of a plurality of
channels, so that it is possible to reduce the size of the
device.
A further object of this invention is to provide an apparatus for
absorptiometric analysis, which is free from decomposition or like
adverse reactions of the reaction liquid which is the subject of
measurement.
According to the invention, an apparatus is provided for measuring
the absorbance of reaction liquids contained in reaction vessels,
at n measuring points for m channels, comprising:
illuminating means for emitting a beam;
means for guiding the beam from the illuminating means to the
reaction liquid contained in m.times.n reaction vessels, at n
measuring points for m channels, the illumination beam guiding
means including m.times.n illumination beam guiding optical fibers,
with every m optical fiber thereof guiding the beam from the
illuminating means to each of the n measuring points;
means for guiding the transmitted beam, including m.times.n
transmitted beam guiding optical fibers for guiding the beam
transmitted through the reaction liquids in the respective
m.times.n reaction vessels;
beam switch means including support means for supporting the beam
emission ends of the transmitted beam guiding optical fibers in a
circle, and in such a way that beams emitted from the beam emission
ends are substantially parallel to one another, a first reflecting
mirror being rotatably provided at a position of incidence of the
beams from the transmitted beam guiding optical fibers, and a
second reflecting mirror for reflecting the beam reflected from the
first reflecting mirror in such a way that the beam reflected from
the second reflecting mirror proceeds along a constant optical
path;
a plurality of slit members disposed along the optical path of the
beam reflected from the second reflecting mirror;
a diffraction grating for diffracting the beam having been passed
through the slit members; and
a photo-detector array, including a plurality of photo-detectors,
for detecting diffracted monochromatic beams from the diffraction
grating.
According to this invention, the measurement of the absorbance of
reaction liquids for a plurality of channels at a plurality of
measuring stations is done by the common diffraction grating of
photo-detector array. Thus, unlike the conventional arrangement
using a plurality of spectrometers, the measurement is free from
errors due to fluctuations of the light-electricity conversion
characteristics among different spectrometers, and complicated
error correction with respect to the different spectrometers is
unnecessary. In addition, the size and cost of the apparatus can be
reduced.
Further, the beam emitted from the single illuminating means (i.e.,
from a single light source) is led through the optical fibers to
the individual reaction vessels. Thus, the apparatus can be
operated and serviced more easily and can consume less power
compared to the conventional structure using a plurality of light
sources.
Further, since light is led to and from the individual measuring
stations through optical fibers, the apparatus can be further
reduced in size. Furthermore, since transmitted beams from the
reaction liquids for a plurality of channels and at a plurality of
measuring stations are selectively led to the slit members with the
rotation of the first reflecting mirror, the switching of
transmitted beams to be detected by the diffraction grating and
photo-diode array can be done at a high speed, so that the
processing speed can be increased.
Moreover, if a light source driven for light emission by a pulse
drive system, e.g., a xenon flash lamp, is used as the illuminating
means, the light energy supplied per unit of time may be low,
though the brightness is high, so that it is possible to avoid
adverse effects of illumination on the reaction liquid. Further,
with the high brightness of the illumination light, the intensity
of the transmitted beam can be detected with a high degree of
precision, even if the filling factor of the optical fibers is so
low that light loss therein is high.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a conventional apparatus
for absorptiometric analysis;
FIG. 2 is a schematic representation of another conventional
apparatus for absorptiometric analysis;
FIG. 3 is an exploded perspective view showing an embodiment of the
apparatus for absorptiometric analysis according to the present
invention; and
FIG. 4 is an axial sectional view showing beam switch means and a
light detection system in the same embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 3 and 4 show an embodiment of the apparatus for measuring
absorbance according to the present invention. A light source 60 as
shown in FIG. 3 is a xenon flashed lamp. It is driven by a pulse
drive system and emits a high brightness beam as light pulses, for
instance with a pulse duration of 3 .mu.sec and at a frequency of
100 Hz. Further, it intermittently emits a beam, for instance 12
times in every 6 seconds, as will be described later in detail. The
beam emitted from the light source 60 is converged by a condenser
lens 62 into a parallel beam, which is incident on the beam
receiving end of a bundle of optical fibers 64 for guiding the
illumination beam (which are 12 in number in the illustrated
example).
A plurality of cassettes 68 (only three thereof being shown), each
supporting four reaction cuvettes 70 arranged in a row, are
arranged in an endless line perpendicular to the row of reaction
cuvettes 70 in each cassette 68. The reaction cuvettes 70 supported
by the individual cassettes 68 have their lower half immersed in a
constant-temperature medium, e.g., warm water, contained in a
thermostatic bath 66. The constant-temperature medium is held at a
predetermined reaction temperature. The cassettes 68 are fed
intermittently along the endless line by transfer means 104, well
known to those skilled in the art, in the direction of arrow A in
FIG. 3 with supported reaction cuvettes 70 partly immersed in the
medium. For instance, they are intermittently moved by transfer
means 104 to a position having been occupied by the preceding
cassette after they have been held stationary for 6 seconds.
Three measuring stations, for instance, are provided on the endless
line at suitable positions thereon, at which positions the
cassettes 68 are held stationary for the period noted above. In
each measuring station, four pairs of beam path defining members 74
and 76, e.g., reflecting mirrors or prisms, are provided. The beam
path defining members 74 and 76 in each pair are disposed on the
opposite sides of each reaction cuvettes 70 in the longitudinal
direction of the cassette 68. A condenser lens 72 having a vertical
lens axis is disposed right beneath each beam path defining member
74. The emission end of each of the optical fibers 64 for guiding
the illumination beam is disposed right beneath each condenser lens
72 such that its optical axis coincides with the lens axis of the
condenser lens 72. A condenser lens 78 having a vertical lens axis
is disposed right beneath each beam path defining member 76. The
beam receiving end of each of optical fibers 80 for guiding the
transmitted beam is disposed right beneath each condenser lens 78
such that its optical axis coincides with the lens axis of the
condenser lens 78. The beam emitted from each optical fiber 64 is
condensed by each condenser lens 72, and its path is then changed
by each beam path defining member 74 to a horizontal path. The
horizontal beam is transmitted through the reaction liquid in each
reaction cuvettes 70. The path of the transmitted beam is diverted
by each beam path defining member 76 toward each condenser lens 78,
so that the beam is condensed in such a way as to be incident on
each optical fiber 80.
Of the 12 optical fibers 64 for guiding the illumination beam noted
above, every four optical fibers are led to each of the three
measuring stations. In each measuring station, the four optical
fibers 64 are led to their respective reaction cuvettes 70. The
optical fibers 80 for guiding the transmitted beam led out from the
reaction cuvettes 70 at the measuring positions constitute a bundle
of optical fibers. They are 12 in number, and four of them are led
out from the respective reaction cuvettes 70 in each measuring
station.
The beam emission ends of the 12 optical fibers 80 are supported by
a support member 82 at positions thereof which fall on a circle.
The support member 82 is secured to the frame of the apparatus. A
shaft 84 rotatably penetrates the center of the support member 82
and extends substantially at right angles to the plane of the
support member 82. The beam emission ends of the 12 optical fibers
80 are uniformly spaced on the support member 82 along a circle
with the center thereof concentric with the axis of the shaft 84.
They are secured to the support member 82 such that they extend
parallel to the axis of the shaft 84. The beam receiving end and
beam emission end of the optical fibers 64 and the beam receiving
end of the optical fibers 80 are all circular in sectional shape.
The beam emission end of the optical fibers 80, however, is
elongated in sectional shape like a slit. The beam emission ends of
the individual optical fibers 80 are secured to the support member
82, in such a way that they extend in the same direction.
The shaft 84 projects from the side of the support member 82,
opposite the side on which the beam emission ends of the optical
fibers 80 are secured. A rotor 86 is secured to the free end of the
projecting portion of the shaft 84. It carries a reflecting mirror
88 mounted on its side facing the support member 82 and at a
position which is adapted to be brought into alignment with the
beam emission end of each optical fiber 80. The shaft 84 carries a
reflecting mirror 90 facing the reflecting mirror 88. The shaft 84
also has a notch formed in its portion on the side of the
reflecting mirror 90 nearer the rotor 86 and also sectionally on
the side nearer the reflecting mirror 88. The rotor 86 has a
see-through hole 86a corresponding in position to the notch of the
shaft 84. The beam emitted from the beam emission end of the
optical fiber 80 aligned to the reflecting mirror proceeds along a
path as shown by a dot-and-bar line. More particularly, it first
proceeds along a path parallel to the axis of the shaft 84 and is
reflected by the reflecting mirror 88 to be incident on the
reflecting mirror 90. The beam reflected by the reflecting mirror
90 proceeds along a path substantially coincided with the axis of
the shaft 84, through the see-through hole 86a of the rotor 86.
A pair of slit members 92, 96 is disposed on the path of the beam
from the rotor 86 (i.e., on the axis of the shaft 84). A condenser
lens 94 is further disposed on the beam path noted above between
the slit members 92 and 96. The slit members 92 and 96 have
respective slits extending in the direction of the elongated beam
emission ends of the optical fibers 80, the section of the emission
ends having a shape corresponding to the slits of the slit members
92 and 96.
The beam having passed through the slit member 96 is incident on
and is diffracted by a diffraction grating 98. The diffracted beam
is incident on a photodiode array 100 consisting of a plurality of
photodiodes 102 arranged in a row. The intensity of the beam for
each particular wavelength is detected by each photodiode 102. More
specifically, the photodiodes 102 convert the incident beam into
electric signals, which are transferred to a calculating unit (not
shown). The calculating unit calculates the absorbance of the
reaction liquid according to the results of detection of the
intensity of the transmitted beam provided from the photodiode
array 100.
The operation of the apparatus having the above construction may be
described as follows. A sample, e.g., a serum of a patient, is
distributed into the four reaction cuvettes 70 supported by each
cassette 68. Predetermined reagents for different examination
items, i.e., GOT, GPT, .alpha.-GPT and amilase are charged into the
respective reaction cuvettes 70. The individual cassettes 68 with
the reaction cuvettes 70 containing respective reaction liquids
(i.e., mixtures of sample and reagent) are intermittently moved by
transfer means 104 in the direction of arrow A in FIG. 3, along the
endless line with the reaction liquids held at a constant
temperature by the constant-temperature medium in the thermostatic
bath 66. They are held stationary, e.g., for 6 seconds, at the
first to third measuring stations. After each cassette 68 is moved
from each measuring station, the succeeding cassette 68 is moved to
that station by transfer means 104.
While the cassettes 68 are stationary, the light source 60, which
is a xenon flashed lamp, is driven to emit beams intermittently, 12
times. The beam emission is caused by a pulse drive system with a
flashing period of approximately 3 .mu.second and a flashing
frequency of 100 Hz. One beam emission period is 0.2 seconds. Thus,
even if the amplitude of the pulse and, hence, the brightness of
the beam, is high, the integral of the amount of beam emitted per
unit time or the total energy (in Watts) of beam transmitted
through the reaction liquid per unit time is extremely low compared
to the prior art case using the halogen lamp. For this reason,
there is no possibility of decomposition or other undesired
reactions of a reaction liquid, even if the xenon flashed lamp with
about 1,000 times the brightness of the halogen lamp is used. Also,
optical fibers of a low filling factor may be used as the optical
fibers 64 and 80 to obtain the measurement of absorbance without
being adversely influenced by the loss of light because of the high
brightness of the beam. The inventor conducted experiments about
the decomposition of bilirubin by illumination of flashlight from
the xenon flashed lamp, and it was confirmed that the decomposition
that results is very little compared to the case of continuous
illumination using the halogen lamp. The same effects may be
obtained by using a mercury flashed lamp, a pulse laser, etc., in
lieu of the xenon flashed lamp serving as the light source 60.
Further, the same effects may be obtained by using an illuminating
means which provides a beam from a halogen lamp, as a
non-continuous beam; by means of chopping, instead of the pulse
drive system light source.
The beam emitted from the light source 60 is coupled, through the
condenser lens 62, to the beam receiving ends of the optical fibers
64. Through these optical fibers 64, the beam is led to the
reaction vessels 70 in the first to third measuring stations. More
specifically, the beam emitted from the beam emission end of each
optical fiber 64 is coupled through the associated condenser lens
72 and beam path defining member 74 and transmitted through the
reaction liquid in the reaction cuvette 70. The transmitted beam is
coupled through the associated beam path defining member 76 and
condenser lens 78 to be incident on the beam receiving end of the
corresponding optical fiber 80. The beam coupled to the optical
fibers 80 is emitted from the beam emission ends thereof supported
by the support member 82. During each stationary period of the
cassettes 68, the transmitted beam is emitted 12 times from the
beam emission ends of the 12 optical fibers 80.
While the transmitted beam is being emitted from the bundle of
optical fibers 80 for the first period, the rotor 86 is held at a
position at which the beam emission end of the first optical fiber
80 in the bundle is aligned to the reflecting mirror 88. When the
emission of the transmitted beam for the first period is over, the
rotor 86 is rotated to a next stationary position, at which the
beam emission end of the second optical fiber 80 adjacent to the
first optical fiber is aligned to the reflecting mirror 88. The
rotor 86 is held stationary at this position during the emission of
the transmitted beam for the second period. When the second period
of transmitted beam emission is over, the rotor 86 is moved again
and is brought to a position, at which the third optical fiber 80
adjacent to the second is aligned to the reflecting mirror 88. This
sequence of operation of the rotor 86 is caused 12 times
successively while the cassettes 68 are held stationary. While the
rotor 86 is intermittently rotated to complete one rotation, beams
transmitted through the reaction liquids in the 12 reaction vessels
at the first to third measuring stations are successively caused to
pass through the slit member 92, condenser lens 94 and slit member
96. It is to be understood that the rotor 86 serves as beam switch
means for independently and successively supplying beam transmitted
through the reaction liquids in the individual reaction cuvettes 70
through the slit member 92, condenser lens 94 and slit member 96.
Since the path of the transmitted beam is regulated by the pair of
reflecting mirrors 88, 90, the transmitted beam emitted from each
optical fiber 80 can be supplied to the slit member 92 without
substantial loss.
The transmitted beam, having been passed through slit member 92,
the condenser lens 94 and slit member 96, is incident on the
diffraction grating 98. The diffracted beam from the diffraction
grating 98 is detected by the photo-detectors 102 of the
photo-detector array 100 for individual predetermined wavelengths.
The slit members 92, 96 are provided for increasing the directivity
of the transmitted beam. While with a single slit, the directivity
of transmitted light is not significantly increased, it can be
substantially increased by providing a pair of slits. Meanwhile,
the beam emission end of the optical fibers 80 has an elongate
shape corresponding to the shape of the slit of the slit members 92
and 96. That is, a beam having an elongate sectional shape is
emitted from the beam emission end of each optical fiber 80. Thus,
the proportion of the transmitted beam blocked by the slit member
92 is very low compared to the case where an ordinary beam having a
circular sectional profile is blocked by the slit member 92. This
means that the light energy of the transmitted beam emitted from
the beam emission end having the elongate shape similar to the
shape of the slit is blocked only slightly by the slit members 92
and 96, so that it can be effectively supplied to the
photo-detectors 102.
Data on the intensity of the transmitted beam detected by the
photo-detectors 102 is stored in a memory of the calculating unit.
While the cassettes 68 are held stationary, the intensity of the
transmitted beam from the reaction liquids in the 12 reaction
cuvettes 70 is obtained for the individual predetermined
frequencies. This data are stored in the memory. They are obtained
and stored every time the cassettes 68 are moved to the next
position.
After the intensity of the transmitted beam with respect to each
cassette has been measured for all of the measuring stations, the
calculating unit reads out data on the intensity of the transmitted
beam which data is obtained with respect to a particular reaction
liquid for the first to third measuring stations and is selected
from among data stored in the memory, thereby calculating the
absorbance. At this time, the absorbance is usually obtained on the
basis of a commonly termed two-wavelength measurement, to eliminate
background noise. More specifically, the difference between the
absorbances with respect to two wavelengths, i.e., a main
wavelength and an auxiliary wavelength, is obtained from the data
obtained at each measuring station. This difference in the
absorbance is multiplied by a preliminarily obtained constant for
conversion to the absorbance with respect to the main wavelength.
In the above embodiment, the wavelength accuracy is high, since the
transmitted beam is incident on the diffraction grating 98 after it
has been passed through the pair of slit members 92 and 96. Thus,
the two-wavelength measurement can be obtained with a high degree
of accuracy, without a deviation in the pattern relating to the
wavelength, or absorbance with respect to the wavelength.
The absorbance obtained for each reaction liquid, in the
above-described manner, is plotted against time, until the reaction
cuvette is brought to the first to third measuring stations, after
addition of the reagent to the sample. Changes in the absorbance,
i.e., the reaction degree, with time thus can be obtained. Whether
the pertinent patient is normal or not with respect to the given
reagent item is judged from the changes in the reaction degree with
time.
It is to be further understood by those skilled in the art that the
foregoing description is for the sole purpose of illustrating the
preferred embodiment of this invention, and that various changes
and modifications may be made to the invention, without departing
from its scope and spirit. For example, the number of channels and
number of measuring stations are not limited to 4 and 3,
respectively, as in the above embodiment, but may be suitably set,
according to the examination items and other factors. Further,
three or more slit members may be provided, instead of a pair of
slit members, between the rotor 86 and diffraction grating 98.
Still further, it is possible to provide the beam switch means
comprising the support member 82, shaft 84, rotor 86 and reflecting
mirrors 88, 90, between the condenser lens 62 and the bundle of
optical fibers 64. In this case, the beam from the light source 60
is successively distributed to the 12 optical fibers, with the
rotation of the rotor 86. Thus, no beam is supplied to the reaction
liquid, with respect to which the measurement of absorbance is not
made. Thus, the influence of the transmitted beam on the reaction
liquid can be further reduced. Finally, while the above embodiment
has used condenser lenses 72, 78 and beam path defining members 74,
76 in guiding beams to and from the reaction liquids, it is also
possible to arrange the beam emission ends of the optical fibers 64
and the light receiving ends of the optical fibers 80 in such a way
that they directly face the reaction cuvettes 70, so that the beam
from the optical fibers 64 is directly incident on the reaction
liquids and the transmitted beam is directly incident on the
optical fibers 80.
* * * * *